hadoop-common-dev mailing list archives

[jira] Commented: (HADOOP-3426) Datanode does not start up if the local machines DNS isnt working right and dfs.datanode.dns.interface==default

Date

Thu, 28 Aug 2008 21:39:44 GMT

[ https://issues.apache.org/jira/browse/HADOOP-3426?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12626757#action_12626757
]
Raghu Angadi commented on HADOOP-3426:
--------------------------------------
My opinion:
> cluster without DNS
IP address should be used without the hostname
> cluster on xen/vmware without DNS
Same as above.
> ... without internet
You mean without network set up? If we can detect it, then it should be a warning and we should
use the localhost interface if that exists. If not it should be a hard error.
> developer laptop on the move running tests/demos
may be need not be handled now.
> Datanode does not start up if the local machines DNS isnt working right and dfs.datanode.dns.interface==default
> ---------------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-3426
> URL: https://issues.apache.org/jira/browse/HADOOP-3426
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.19.0
> Environment: Ubuntu 8.04, at home, no reverse DNS
> Reporter: Steve Loughran
> Assignee: Steve Loughran
> Priority: Minor
> Attachments: hadoop-3426.patch, hadoop-3426.patch
>
>
> This is the third Java project I've been involved in that doesnt work on my home network,
due to implementation issues with java.net.InetAddress.getLocalHost(), issues that only show
up on an unamanged network. Fortunately my home network exists to find these problems early.
> In hadoop, if the local hostname doesnt resolve, the datanode does not start up:
> Caused by: java.net.UnknownHostException: k2: k2
> at java.net.InetAddress.getLocalHost(InetAddress.java:1353)
> at org.apache.hadoop.net.DNS.getDefaultHost(DNS.java:185)
> at org.apache.hadoop.dfs.DataNode.startDataNode(DataNode.java:184)
> at org.apache.hadoop.dfs.DataNode.(DataNode.java:162)
> at org.apache.hadoop.dfs.ExtDataNode.(ExtDataNode.java:55)
> at org.smartfrog.services.hadoop.components.datanode.DatanodeImpl.sfStart(DatanodeImpl.java:60)
> While this is a valid option in a production (non-virtual) cluster, if you are playing
with VMWare/Xen private networks or on a home network, you can't rely on DNS.
> 1. In these situations, its usually better to fall back to using "localhost" or 127.0.0.1
as a hostname if Java can't work it out for itself,
> 2. Its often good to cache this if used in lots of parts of the system, otherwise the
30s timeouts can cause problems of their own.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.